It is known to cool the outer periphery or "back iron" of a stator in a dynamoelectric machine such as a generator by providing cooling grooves in a housing which surrounds the stator core. A coolant, typically oil, is conveyed through the cooling grooves in contact with the outer periphery of the stator core for cooling the stator core. Where the stator windings have end turns which extend beyond the axial ends of the laminated stator core, special provisions have also been made for cooling these end turns. For example, U.S. Pat. No. 3,531,668 discloses an induction motor cooling arrangement wherein special retaining members are located adjacent the stator core ends which are formed with cooling fluid orifices. U.S. Pat. No. 3,648,085 is directed to a liquid cooling arrangement for dynamoelectric machine wherein special annular distributing manifolds or spray rings having atomizing spray nozzles are located on opposite sides of the stator core for cooling the end turns. These known cooling arrangements are disadvantageous in that they are relatively expensive to manufacture and also to clean or maintain. The additional cooling structures required in these known cooling arrangements also can create friction and windage losses to reduce the operating efficiency of the dynamoelectric machine.
U.S. Pat. No. 2,285,960 discloses a dynamo-electric machine wherein axial ducts are drilled through the numerous laminations of the stator core for conveying coolant axially for cooling stator winding end turns. One problem associated with this type of cooling arrangement is that it requires drilling the entire stator core which is relatively expensive. Moreover, this known cooling arrangement is relatively difficult to clean and maintain. See also U.S. Pat. No. 4,864,176.